The use of electrophotographic techniques on microfiche-like film has resulted in a record processor apparatus which is versatile and extremely useful for the micro-recording and storing of information. One such apparatus is the commercially available System 200 record processor manufactured and distributed by A. B. Dick/Scott of South Hadley, Mass.
This system is generally described in U.S. Pat. Nos. 3,972,610; 3,916,828; and 3,927,639. Other such systems are described in U.S. Pat. Nos. 3,683,852 and 3,936,854.
In this type of apparatus, a film having a small latent electrostatic image, usually greatly reduced in size, is developed by exposing, for a short period, only the area having the image to a toner-bearing liquid, sometimes referred to as a monobath. This liquid toner usually comprises a suspension of very fine electroscopic particles colloidally suspended in a liquid carrier. Although a succession of liquids could be used, for convenience most, if not all, commercial applications employ a single liquid and the present invention will be described in this environment.
In most prior art systems, the liquid toner is usually caused to flow across the film area to be developed for a period and the area exposed thereafter to air or vacuum to aid in drying the liquid.
Although the prior art methods and apparatus for applying the toner have proven, over all, to produce acceptable results, certain problems have been found to exist. On occasional copies, there were found to be swirls or streaks and lack of definition in the developed image.